Polls show Macron's En Marche party winning most of seats but turnout estimated to be just over 40 percent.

French President Emmanuel Macron's party and its allies have secured a powerful mandate after winning a commanding majority in the country's parliamentary election, according to official results.

With 97 per cent of votes counted in Sunday's poll, Macron’s year-old La Republique en Marche (The Republic on the Move, LREM) gained 285 seats in the 577-member National Assembly.

Another 40 seats have been won by LREM's allies, the centrist Democratic Movement of Justice Minister Francois Bayrou.

Some 33 seats remained to be assigned.

The vote comes just a month after 39-year-old Macron, a former banker, became the youngest head of state in modern French history, promising to clean up French politics and revive the Eurozone’s second-biggest economy.

After four failed attempts to enter the National Assembly, recently defeated presidential candidate and National Front leader Marine Le Pen was finally elected as an MP in the far-right stronghold of Henin-Beaumont, northern France.

Her National Front party is predicted to secure six seats.

Turnout, though, was on course for a record low, a sign of voter fatigue after seven months of campaigning and voting - and also of disillusionment and anger with politics that could eventually complicate Macron's reform drive.

Interior Ministry data showed turnout was 35.33 percent at 15:00 GMT, 10 points lower than at the same time in 2012.

Three pollsters projected turnout to be at 42-43 percent at the close of polling, a record low in the post-war Fifth Republic.

"People know it's already a done deal," Alex Mpoy, a 38-year-old security guard, told Reuters TV in Paris, echoing the apathy of many voters who did not intend to vote.

Reform drive

Many of Macron's lawmakers will be political novices, something which will change the face of parliament at the expense of the conservative and socialist parties which have ruled France for decades.

Macron will need to keep the diverse and politically raw group of lawmakers united behind him as he sets out to overhaul the labour code, cut tens of thousands of public-sector jobs and overhaul an unwieldy pension system.

Trade unions have said Macron must listen to their demands and not use his majority to bulldoze policy reforms through, or else face unrest.

The spokesman, Steffen Seibert, hailed the strong showing for Macron's year-old Republic on the Move (REM) in a tweet, adding that Merkel wished for "further good cooperation for Germany, France, and Europe".

Foreign Minister Sigmar Gabriel also welcomed the vote's outcome, tweeting that it paved "the way for reforms in France+Europe".

Macron has forged the beginnings of a strong working relationship with the German leader since his election last month, despite significant differences over several issues including stewardship of the euro.

He chose Berlin for his first trip abroad as president.

At a joint press conference, Merkel threw her support behind Macron's call for a "historic reconstruction" of the European Union, even expressing some openness to a possible change to key treaties governing the bloc.